【SwiftUI】アプリの初回起動時のみCoreDataに初期データを持たせる方法

import SwiftUI
import CoreData

struct ContentView: View {
  @Environment(\.managedObjectContext) var context
  @FetchRequest(
    entity: Category.entity(),
    sortDescriptors: [NSSortDescriptor(keyPath: \Category.date, ascending: false)],
    animation: .default
  ) var categorys: FetchedResults<Category>
  
  func loadData() {
    if self.categorys.count == 0 {
      let category = Category(context: self.context)
      
      category.name = "未分類"
      category.date = Date()
      do {
        try context.save()
      } catch {
        let nsError = error as NSError
        fatalError("Unresolved error \(nsError), \(nsError.userInfo)")
      }
    }
  }
  
  var body: some View {
    TabView {
      TaskListView()
        .tabItem { Text("Task") }
      CategoryListView()
        .tabItem { Text("Category") }
    }
    .onAppear(perform: loadData)
  }
}